Prostate cancer

Prostate cancer is a group of cancerous cells (a malignant tumor) that begins most often in the outer part of the prostate. It is the second most common type of cancer in men in the United States. Skin cancer is the most common. Of all the men who are diagnosed with cancer each year, more than one-fourth have prostate cancer.

Detecting prostate cancer

Early and accurate detection of prostate cancer offer the best hope of cure for the disease.

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The American Cancer Society and American Urological Association recommend annual examinations for prostate cancer for men at risk (all men over 50; or men over 40 with family history of prostate cancer; or African-American men). This is currently done by two procedures:

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• Digital rectal examination (DRE) -- During this procedure, the physician inserts a gloved, lubricated finger into the rectum in order to feel the size and shape of the prostate to find areas that are for hard or lumpy, which may indicate cancer. DRE can only detect abnormalities in one area of the prostate (the zone that can be felt through the rectum). Fortunately, this is where most prostate cancers arise.
• Blood test for prostate-specific antigen (PSA) -- a lab measures the levels of PSA in a blood sample. Under normal circumstances, PSA is not found in the blood, but levels lower than 4 ng/mL (nanograms per milliliter) are considered normal. Levels greater than 10 ng/mL are considered abnormal. PSA levels between 4 and 10 ng/mL are considered to be borderline. PSA tests for prostate cancer are a subject of some controversy among clinicians and researchers. This is because some men who have prostate cancer do not have elevated PSA (>4 ng/mL), while some men with elevated levels do not have prostate cancer. This is far from being a perfect test, but it is the best method currently and used commonly.

Elevated PSA levels can occur for many reasons. They may rise in men who have prostate cancer, benign prostate hyperplasia (BPH), or an infection in the prostate (prostatitis). To maximize the accuracy of a PSA test: (1) Don’t ejaculate for 2 days prior to having a PSA test as this can raise PSA levels, and (2)inform your physician if you are taking Proscar, Avodart or Propecia. These drugs, used to treat BPH and baldness affect the metabolism of testosterone throughout your body and will likely lower your PSA levels. Also, (3) the DRE needs to be performed after drawing blood for the PSA test, as palpation of the prostate can stimulate it to produce PSA and lead to elevated PSA levels in the serum. Some herbal supplements can also affect PSA levels. Discuss any supplements you are taking with your physician prior to having a PSA test.

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The most recent trend is to consider the rate of change of the PSA level as an indication of the risk of cancer. This requires at least two PSA tests be done over a period of time. Abnormal DRE or high serum PSA levels are reasons for a medical follow up. The results of these tests will help to determine whether further tests are necessary to check for cancer.

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When the total PSA blood test is in the grey zone (between 4 and 10 ng/mL) and the DRE is normal, the percentage of free PSA (unbound to other proteins) in the blood is used to distinguish between BPH and prostate cancer. A low value for percent-free PSA indicates a higher probability of prostate cancer.

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Currently, a biopsy is the only procedure that can definitively diagnose prostate cancer. It is performed when digital rectal examination shows abnormalities or a patient has high total PSA in the serum. A biopsy gun inserts and removes hollow core needles (usually three to six for each side of the prostate) in less than a second. The needles are very fine and remove only small cores of tissue. In this way, small 'samples' of the prostate are removed. The tissue samples are then examined under a microscope to determine if cancer cells are present and to evaluate the extent of the cancer. Some men have reported that this is the most physically uncomfortable part of their experience of being diagnosed with prostate cancer. (Patients can request that an appropriate anesthetic be used.)

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